Nonmagnetic steel wire



and State of Pennsylvania,

Patented Nov. 10, 1925.

uNiTEn -STATES PATENT ,OFFl

PORTER H. BRACE, OF WILKINSBURG. PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC MANUFACTURING COMPANY, A CORPORATION 01! PENNSYLVANIA.

NONMAGNETIC STEEL WIRE.

No Drawing.

. To all who'mit may concern:

Be it known that I Pon'rnn H. BRACE, a citizen of the United tates, and a resident of Wilkinsburg, in the county of Allegheny have invented a new and useful Im rovement in Nonmagnetic Steel Wire, of which the following is a specification. I

This invention relates tov alloys, more particularlyto an iron alloy wh1ch has high tensile strength and is substantially non-- etic. aterials of this kind are suitable for a variety of uses especially in delicate measuring instruments, such as electric meters and the like. Such apparatus usually includes a rotatable cop er disk mounted between the poles of an e ectromagnet and revolving about a steel shaft. In order to prevent losses due to stray magnetization, it is deof withstan sirable that the steel shaft be non-magnetic and also have a high tensile strength in order to allow a minimum weight of rotating arts. p My invention is designed to provide such a material, it being amon the objects thereof to produce a steel al oy which is nonmagnetic, has a high tensile strength, a high elastic limit which is hard and is capable ding cold working. In practising my invention, I provide an alloy containing iron and carbon, and several alloying materials, such as manganese, nickel, chromium, and usually silicon and vanadium. Generally, the compositions of my new alloy ranges as follows:

7 Carbon .0.5-"1.5

.the remainder being iron and minor impurities. H

The manganese and nickel added to the iron render the same non-magnetic. The

. strength an Application filed April 21, 1921. Serial No. 463,149.

nickel also tends to prevent oxidation of the alloy during working. The addition of chromium increases'the strength of the steel and further prevents oxidat1on thereof.

I generally add silicon to the alloy as it greatly improves the forging characteristics of the same, retards oxidation, and increases the hardness, the strength and the elastic limit of the alloy. Vanadium renders the grain size of the alloy small and thus increases the strength thereof. I

I have found that certain proportions of ingredients groduce an alloy having high low magnetic ermeability. iIhe composition of such an al oy is as folows:

the remainder being iron, and the minor impurities usually found in' high grade alloy steels.

- This alloy may be forged, rolled and drawn cold. Wire made therefrom has a tensile strength of 250,000 to 300,000 pounds per square inch and an elongation of- 10 to 20% inten inches of length. The magnetic mass susceptibility of the wire is below .004.

This material, on account of its high tensile strength and low susceptibility, is especially suited for use in delicate electricalv instruments where stray magnetic fluxes are capable of causing disturbances, and finds particular use in the shafts of electric meters.

Although I have specifically set forth a composition of an alloy which gives the desired results, it is to be understood that my invention is not limited to the percentagds set' forth specifically but the compositions.

of my new alloys may varywithin wide limits within the scope of the claims appended hereto.

I claim as my invention:

1. A substantially non-magnetic ferrous alloy comprising 10 to 18 per cent of mananese 2 to 8 per cent of chromium and 5 Per centt o 10 per cent of nickel. g igi 1g A ubstantially non-magnetic ferrous C1116 6 2 oy comprising approximatel 2 per c t P 075 5 of c omium, approximately 15 per cent f 3 0.15 15 manganese and approximately 5 per cent of mckel. In testimony whereof, I have hereunto 3. An iron alloy comprising iron, carbon, subscribed my name this 11th day of April minor im urities and the following in- 1921. 10 gredients 1n the proportions stated: PORTER H. BRACE. 

